Is UDK's default AO different then baking an AO Map?

Chase

Just wondering if having AO checked on or off in UDK is the same thing as rendering out an AO Map in a 3d program and applying it to the Diffuse?

Shadownami92

Not necessarily, when people bake out their AO for their diffuse maps it's generally used just to make textures pop more and it can be used as a guideline for painting your diffuse texture among other things.

The main difference between UDK's AO and baking AO is that baking AO will act on each single object individually. While UDK's AO acts on a scene as a whole. Therefore UDK's AO can help art assetts blend together as a scene better. I don't necessarily have any good images to explain it at hand but I guess here is an example.

If you bake AO on a wall and put it into your diffuse, and then you bake AO on a shelf assett and put it in the diffuse. You won't get a darkening of edges in UDK when you put the shelf next to the wall. While UDK's AO will get you the effect of the shadowy darkening around the edges of where the shelf attaches to the wall in your UDK scene.

Chase

That makes sense. I was wondering how AO baking for diffuse textures got you that kind of result for an entire level. I'm pretty sure this is a pic that describes what you were saying. Not sure if it was done in UDK or some 3d program.



How would I apply AO to an entire scene in 3ds Max? I just read a little bit about post processing on the Unreal website and AO was mentioned in it. I'm just learning about creating shaders, which has my mind completely flat lined at the moment. Piecing everything together, albeit slowly then I'd like. Thanks for the response Shadownami!

AlexLeighton

If you're in Max 2012 just turn your viewport to Realistic and it should do AO by default. Older versions, you need to turn on hardware rendering in the viewport menu and then I think you need to tell it you want AO on in that menu.

Captain Salty

Correct me if I'm wrong but I'm under the impression you generally don't want to bake AO into your assets that are going to be used in a game engine.

Ace-Angel

Unless the game engines supports Indirect/Shadowed Diffuse lighting, in which case, only parts of a mesh which are exposed to the shadows, show the AO map.

Uncharted did this to great extent.

Captain Salty

So, the game engine knows when it should or shouldn't show AO that's been baked in? Dependant on the current lighting in the scene?

Ace-Angel

Nope, you need to setup the material for that on your own through Custom's. Read Naughty Dog's implementation of it, it should be easy enough to understand.

Chase

I can't find the realistic setting anywhere. I'm using Max 2012 too, but I did enable shadows and AO in the Shadow Options of the viewport. Would that be the same thing?